Producing oxalates from formates



Sept. 2 1924. 1,506,872

W. WALLACE PRODUCING OXALATES FROM FDRMATES Filed lax ch 23, 1920 ZE'male oontazinefl @51 um; Z 7

Patented Sept. '2 1924.

UNITED STATES PATENT OFFICE.

warm wannacn, or m sannn, new voax, assrefion roonnmmr mm OEEIICAI OOEPAINY, OI NIAGARA FAILS, NEW YORK, A COBPOBA'I'IOR'OI m YORK.

PRODUCING OXALA'I'ES FROM FORMA'I'ES.

Application fled March 23, 1920. Serial 1m. seam.-

To all whom it may conccm:

Be it known that I, WALTER WALLACE, a citizen of the United States, and. resident of La Salle', in ,the county of Niagara and State of New York, have invented certain new and useful Improvements in Producin Oxalates from Formates, of which the fo lowing is a specification.

This invention relates to improvement in producing oxalates of the alkali metals from formates of these metals and has for its object to increase the yield of oxalate without excessive production of carbonate as a by-product.

The common method is to putthe solid formats, for example sodium formats, into a heated vsssel and bring it as rapidly as possible up to the conversion temperature. It is necessary in order to obtain a good yield of oxalate that the conversion of the formats take lace .as far aspossible at the most favorab e temperature. ,For example,

sodium formats when heated decomposes as follows?- ths formation' of carbonate increasing if the .when the formats is rapidly brought to from380 0. to 440? 0. While this is readily done with very small quantities of the material, as for instance in a test tube, in the heating of large masses of solid alkaline formats to' such temperature, those portions which are first heated by the walls of-the vessel are apt to become overheated unless the tem erature of the walls of the vessel is kept slow 440 0., whereas if, the walls of the vessel are kept below such temperature but above 380? 01 the sodium oxalate immediately formed on the walls, in the form of a highly non-conducting sponge of solid oxalate and gas, permits only-slow heating of the remaining portion of'jthe.

material, with the result that the conversion of the remainder of the formate takes place-"at substantially lower temperatures than the most' favorable converslon temperature, with the resulting. formation of thevessel that the sodium formats, on .it's

introduction into the vessel, is not-rapidly converted in contact with the walls as described above, then the whols' mass slowly increases in temperature with the result that the whole conversion takes place at a temperature lower than the most favorable conversion temperature withia resulting excess of carbonate formed. The use of stirring does not overcome these difliculties.

By this; invention, the formats is melted in one vessel, below the conversion temperature, then supplied molten .to the reaction best conversion. temperature and there converted in a few minutes, with approximate- 1y 90% yieldof oxalate and aminimum of vessel which is .kept heated to maintain thecarbonate. vBy this means no heat need be molten formats introduced to' between- 380 0. 'and 440 Further, the formats being introduced in a'liquid condition, is heated much more rapidly than when introduced in. .the form of a solid. Further, the conversion is exothermic, and when this begins in the mass of liquid during its heating in the conversion vessel the rapid and almost simultaneous rise of temperature attainment of a temperature within the most favorablegconversion range and very considerably reduces the period during whichconversion is proceeding at temperathroughout the entire mass. accelerates the I tures lower than the most favorable range. This is because the exothermic heat is not dissipated during slow conversion of 'rela tively small quantities at a time, but 1s utilized owing to the sudden release of nearly the'entire amount in the mass.

For example, sodium' formats ismelted, heated to about 270 0., then fed into a con-. version vessel previouslt heated to 440 0.

to rovide a desired conversion temperature of tween 380 0. and 440 0., this giving the most rapid rate of conversion wlthout overheating and the best yield of mately 90% of sodium oxalate.

process is shown in the acc'ompan drawby burner 2, an

approxi- I A suitable apparatus forcarrying out the in? wherein 1 represents theg remeltmg vespipe 3 having valve 4 to the lower conversion vessel 5 having burners 6 producing the desired conversion temperature, a vent 7, and clean out 8.

While the process above described en ables .alkaline formate to be converted with maximum yields of oxalate, without the addition of other substances, should it be desired to add caustic alkalis to the sodium formate, as has been recommended by some inventors for the purpose of improving the yield of oxalate, it is necessary that this be added to the molten formate immediately before running it into the conversion vessel, since it is impossible to maintain the formate without decomposition in a molten condition in presence of caustic alkali. In the case of materials to be added other than caustic alkalis, these are also most conveniently added to the formate when it is in a molten condition.

What is claimed is:

V 1. The process of producing an oxalate from a formate which consists in suddenly heating melted formate from a temperature below that of decomposition to a desired higher temperature for conversion to oxalate by passing the melted formate at the lower temperature into a zone heated to .at least the desired higher conversion temperature.

2. The process of producing an oxalate from a formate which consists in suddenly heating melted forma-te from a temperature below that of decomposition to a desired higher temperature for conversion to .oxalate by passing the me ted formate at the lower temperature into a zone heated to such higher temperature as is sufficient in conjunction with the exothermic heat of reaction to effect the desired rapid conversion to oxalate.

3. The process of' roducing an oxalate from a formate whic consists in melting a charge of formate in one vessel at a comparatively low temperature, discharging the molten formate charge into a second vessel heated to at least equal temperature, and suddenly raising the temperature of the molten formate charge in the second vessel to effect the desired rapid conversion to oxala te.

4. The] process of producing an oxalate from a formate which consists in passing melted formate at a temperature below 290 G. into a vessel heated to a temperature such as to rapidly raise the temperature of the formate to between 380 C. and 440 C.

5. The rocess of producing an alkali metal oxa ate from a formate' of the same alkali metal which consists in melting the formate and heating the molten formats, the latter being so treated and heat being so applied thereto as the temperature thereof reaches 27 0 0., as to cause a sudden rise in the temperature of the entire mass.

6. The process of producing an alkali metal oxalate from a formats of the same alkali metal which consists in melting the formate and heating the molten formate, the latter being so treated and heat being so applied thereto as the temperature thereof reaches 270 C., as to cause a sudden rise in the temperature of the entire mass to between 380 C. and 440 C.

7. The process of producing sodium oxalate from sodium formate which consists in melting the formate and heating the molten for'mate, the latLer being so treated and heat being so applied thereto as the temperature thereof reaches 270 C., as to cause a sudden rise in the temperature of the entire mass'and continuing the heating to complete the conversion.

8. The process of producing sodium oxa ate from sodium formate which consists in melting the formate and heating the molten formate, the latter being so treated and heat being so applied thereto as the temperature thereof reaches 270 0., as to cause a sudden rise in the temperature of the entire mass to between 380 C. and 440 C.

9. The process of producing an oxalate from a formate which consists in melting the formate, pouring the molten formats upon a more highly heated surface, and applying further heat to the poured formate such as to cause a sudden rise in the temperature thereof to the desired conversion point.

10. The method of producing an alkali metal oxalate, which consists in melting the formate, pouring the molten formate upon a more highly heated surface, and applying such further heat to the poured formate such as to cause a sudden rise in the temperature thereof to the desired conversion point.

11. The method ofproducin sodium oxalate from sodium formate w ich consists Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,506,872, granted September 2, 1924. upon the application of Walter lVallace, of La Salle, New York, for an improvement in Producing ()kalatcs from Formates, an error appears requiring correction as follows: Pa e 2. line 84, claim 7, after the Word mass strike out the words and continuing the heating to complete the conversion and that the said Letters Patent should be read with this correction therein that the same may conform. to the record of the case in the Patent Office.

Signed and sealed this 14th day of October, A. D. 1924.

SEAL KARL FENNING,-

Acting Commissioner of Patents. 

